A. Field of the Invention
This invention relates to a net fabric with a three-dimensional structure to be processed into a net product.
B. Description of the Prior Art
There has been recently known in the art a net product made of a three-dimensional net material which exhibits increased cushioning properties in spite of being formed into a reduced thickness as compared with a pad material such as urethane or the like and has a number of voids formed therein to a degree sufficient to permit it to exhibit enhanced breathability. The net material is so constructed that a front mesh layer and a rear mesh layer are connected to each other by means of a number of piles arranged therebetween, resulting in being configured into a truss structure (three-dimensional structure). Such construction permits the net product to provide an elastic structure which has resistance to setting and exhibits both a property of satisfactorily distributing a pressure of the body and a property of impact absorbing. Net products made of such a net fabric include, for example, a seat for a vehicle such as an automobile and the like.
The net material of a three-dimensional structure, as described above, includes the front mesh layer, the rear mesh layer, and the piles knittedly incorporated between the front mesh layer and the rear mesh layer and acting as an intermediate layer. When it is in the form of a starting material (a net fabric to be processed into a net product) prior to being converted into any desired net product, it has a strip-like configuration of a continuous length and a required width. The net fabric is generally provided in the form of a roll fabric wound in a roll-like shape. A processor or manufacturer of such a net product rotates the roll fabric in a direction of unwinding it, to thereby draw out it. Then, the roll fabric thus drawn out is cut into a required length and subjected to any desired processing such as vibrational welding, sewing or the like, to thereby provide a desired net product.
Unfortunately, in the conventional net fabric to be processed into a net product, the configuration of each of the front and rear mesh layers and the size thereof, as well as the knitting or weaving conditions such as the number of piles knitted or woven between both mesh layers are inevitably rendered substantially constant throughout the whole region of the net fabric. This causes the compressibility of the net fabric in the thickness direction thereof to be substantially constant over the whole region. The compressibility is determined in view of various properties such as elasticity, damping properties and the like demanded by applications of a net product made of the net fabric. Thus, when the net product is used for a seat for an automobile, the net fabric with a three-dimensional structure therefor is so manufactured that the entire net fabric may exhibit compressibility suitable for the automobile seat.
Thus, in order to make the net fabric with compressibility suitable for the properties required for the net product, in the portion of the net fabric to be processed, the compressibility is relatively low and the compressive elastic modulus is relatively high, to thereby render operation of cutting the portion troublesome because the elasticity of the portion being cut causes a resistance to the cutting. The cutting operation generally involves cutting a roll of the net fabric into net fabrics with a predetermined length and then cutting the net fabrics into desired shapes by means of a press machine, a cutter equipped with a cutting blade, a water jet type cutter using pressurized water or the like while keeping them laminated or superposed on each other. Unfortunately, during the cutting of the net fabrics laminated on top of each other, the resistance described above is apt to cause positional mismatch therebetween. Also, a reduction in compressibility causes vibrational welding operation, which is a treatment of processing ends of the net fabric (end treatment) or sawing operation to be troublesome.
The present invention has been made in view of the foregoing disadvantage of the prior art.
Accordingly, it is an object of the present invention to provide a net fabric of a three-dimensional structure which is capable of facilitating processing of the net fabric such as cutting, welding or sewing during manufacturing of a net product made from the net fabric.
It is another object of the present invention to provide a net fabric of a three-dimensional structure which is capable of simplifying processing of the net fabric such as cutting, welding or sewing, leading to a reduction in manufacturing cost of a net product made of the net fabric.
In accordance with the present invention, a net fabric of a three-dimensional structure, which can be used as a raw material for a net product, is provided. The net fabric includes a front mesh layer, a rear mesh layer, and a plurality of piles for coupling the front mesh layer and rear mesh layer to each other therethrough. In the net fabric thus generally constructed, a first portion of the net fabric to be processed in processing steps for manufacturing of the net product is relatively increased in compressibility in the thickness direction thereof as compared with that of the remaining or second portion thereof.
In a preferred embodiment of the present invention, the difference in compressibility between the portion of the net fabric to be processed and the remaining portion thereof is set to be 5% or more.
In a more preferred embodiment of the present invention, the difference in compressibility between the first portion of the net fabric to be processed and the remaining or second portion thereof is set to be within a range between 10% and 70%.
In a preferred embodiment of the present invention, the compressibility is adjusted by the density of the net structure of the net fabric.
In a preferred embodiment of the present invention, the density of the net structure is adjusted by adjusting any one element selected from the group consisting of the mesh configuration of the front mesh layer, the mesh size of the front mesh layer, the mesh configuration of the rear mesh layer, the mesh size of the rear mesh layer, the density at which the piles are arranged, the length of the piles between the front mesh layer and the rear mesh layer, the thickness of the piles, and any combination of these elements.
In a preferred embodiment of the present invention, the compressibility is adjusted by varying the material of construction for the fibers used in at least one of the front mesh layer, rear mesh layer and piles.
In a preferred embodiment of the present invention, the compressibility is adjusted by varying the type of the fibers for at least one of the front mesh layer, rear mesh layer and piles.
In a preferred embodiment of the present invention, the portion of the net fabric to be processed includes at least a side edge portion of the net fabric of a predetermined width which is defined along each of side lines thereof.
In a preferred embodiment of the present invention, the portion of the net fabric to be processed includes at least a cut portion of a predetermined width defined along each of cutting lines thereof.